Modern emissions requirements for many internal combustion engine have rendered aftertreatment systems necessary in many applications. Certain aftertreatment systems operate by storing a reagent—for example a NOx reductant—on a catalyst surface so that subsequent emissions may react with the stored reagent. However, presently available systems suffer from some drawbacks. The amount of reagent that can be stored on the catalyst is variable at different operating conditions, including variability with temperature. In certain systems, the storage capacity of the catalyst reduces with temperature to the extent that the reagent may be released unreacted. Many reagents are themselves regulated or considered undesirable materials for direct release into the atmosphere. Therefore, presently available systems must select between a variety of less desirable solutions, including oversizing the storage catalyst, adding a cleanup catalyst, operating the engine in a very conservative manner with inhibited performance, and allowing the aftertreatment system to operate as a less capable system while more aggressively reducing emissions in other areas such as during the combustion event. Each of these solutions increases expense, or decreases the performance and/or reliability of the application. Therefore, further technological developments are desirable in this area.